"Shaken, not stirred," is how James Bond orders his vodka martinis in the movies. The fact is, martinis, like many "spirit forward" cocktails, are designed to be stirred. Shaking gin (or vodka) and vermouth leads to a cloudy, aerated drink with little chunks of ice in it, not the smooth, silky nectar Bacchus intended.

"Unlike moustaches and bow ties, the shake vs. stir divide is not an arbitrary byproduct of bartender groupthink," insists Adam Stemmler, the award-winning San Diego-based bartender behind Blind Tiger Cocktail Co. "There is sound reasoning behind when each is appropriate."

Both methods cool your drink and dilute the alcohol just slightly for an easier drinking experience. But shaking aerates and "emulsifies" a cocktail — important for most drinks containing fresh citrus, dairy or eggs, which need a proper blending to really work. For the aforementioned "spirit forward" drinks (cocktails that contain a mixture of different alcohols with no "mixers" involved), shaking is not necessary, and can negatively impact the look and sometimes even the taste of the cocktail. With that in mind, here are five drinks that you can ruin by shaking and ought to stir, and two we enjoy finger stirring.

Sazerac:(whisky or Cognac, simple syrup, bitters, absinthe rinse)"Shaking a Sazerac or an Old Fashioned aerates the tannin component of aged brown spirits like whisky or Cognac, and leaves a thin, frothy and dilapidated cocktail that sacrifices the silky mouthfeel that stirring maintains," says Stemmler. In essence, all the bitter, earthy stuff the booze extracted from the wood barrels originally to round out the spirit is now sitting at the top of your glass like sludge.